A156148 - OEIS

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A156148

Numbers k such that prime(prime(k)) + 2 == 0 (mod prime(k)), where prime(p)=A000040(p) is the p-th prime.

1

5, 20, 51891, 51893

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

No additional terms up to k=500,000. - Harvey P. Dale, Jul 12 2022

LINKS

Table of n, a(n) for n=1..4.

FORMULA

a(n) = A000720(A156149(n)).

MATHEMATICA

Select[Range[52000], Mod[Prime[Prime[#]]+2, Prime[#]]==0&] (* Harvey P. Dale, Jul 12 2022 *)

PROG

(PARI) p=c=0; until(0, until( isprime(c++), p=nextprime(p+1)); (p+2)%c & next; print1( primepi(c)", "))

CROSSREFS

Sequence in context: A213148 A202860 A344709 * A224867 A156824 A053002

Adjacent sequences: A156145 A156146 A156147 * A156149 A156150 A156151

KEYWORD

hard,more,nonn

AUTHOR

M. F. Hasler, Feb 04 2009

STATUS

approved